Origin

The Romans referred to the thin curve of the waxing moon early in its cycle as luna crescens, ‘growing moon’. Crescens comes from Latin crescere ‘to grow’, the source of many English words such as the late 19th century curved croissant (the French form of crescent), accrue (Late Middle English), decrease (Late Middle English), and increase (Late Middle English). From being applied to the moon the word came to be applied to anything of that same shape. See also crew